KCBS’ Patti Reising Reports

UCLA psychiatry professor Dr George Bartzokis studied the brain circuitry responsible for motor control. Of particular interest to him was the insulation on the circuits. It's known as myelin, which is a sheet of fat coating nerve fibers in the brain that help them fire signals quickly.

"It reduces the amount of time you have to wait until you send the next signal," said Bartzokis. "So that would be like increasing the bandwidth of the Internet of your brain."

Bartzokis studied 72 healthy men, and found that their "bandwidth" or myelin started deteriorating around the age of 40, causing their motor skills to decline, albeit slowly.

"When you're younger you're a little slower, but then you speed up until you're about 40, then you start going back down," said Bartzokis.

But he emphasizes that not all brain activity starts slowing at 40. There's some evidence that suggests the circuitry responsible for higher level reasoning starts slowing down around ten years later.

(MGO)